Method of refining mineral oils by means of fluorinate aliphatic hydrocarbon compounds



Patented June 13, 1939 PATENT orncs 7 2.1m nun-non 0F IEI'INIHG mm! OIIS BY MEANS OF I'LUOBINA'I'B MATH} ll!- DROCARBON COMPOUNDS No Drawing. 5

I'l Serial No. um;

1: Claims. (on. nae-1:)

Thisinvention relatestotherefining oihydrocarbon oil and more particularly to solvent extraction and solvent dewaxing of mineral til by means of organic fluorine and this application is a continuation in part of application Serial No. 23,130, filed May 23, 1935, for Method of refining lubricating uls.

The invention contemplates the separation of parafllne type hydrocarbons from nim-parafllnic ones by solvent extraction and further the separation of solid hydrocarbons, or wax. from those which are liquid at low temperatures, by theme of suitable nominated solvents, and for the purpose oi producing high quality lubricating oils of low pour point.

In our copending applications Serial Hos. 22.914 and 23,130, we have disclosed that certain liquid or liquefied organic fluorine compounds are specially advantageous for dewaxing and that others have special advantages in solvent extraction of mineral oils.

In continuation of this experimental work a large number of aliphatic and aromatic fluorine and other halogen containing cnmpoimds were prepared and their behavior and suitability in solvent refining and solvent of mineral oils were investigated and became known. Also certain rulesastotheinfluenceottheintroduction of chlorine and/or bromine into certain aliphstic and aromatic on the one handandthatoItheinh-oductionoloneormore fluorine atoms on the other hand became apparent as willbenoted Iromthe descriptionofour invention.

Hie respective'selective solvent action of, for example. phenol and aniline is well known. It is also known, that, if one or more chlorine atoms are introduced into the phenyl radical, the solvent power of the chlorinated compounds. chlorophenol and chloro-aniline, is much greater than that of phenol and aniline. Solvent power of a. selective solvent is generally measured by relationships between amount of selective solvent used and quality of rafllnatc obtained. For example. generally one volume of parn-chlomphenol will produeealikeamount ofreflnedoiloi' the same quality as two volumes of phenol will produce. The more powerful it seleclive solvent is the less satisfactory is usually its selectivity, that is, its ability to dimolve only the III viscosity index by of a. mineral in] and to leave imdissolved all the high index compounds, for example.

Itisknownthatbmminewlllacthiasimilar manner to chlorine when introduced into organic,

especially aliphatic, solvents with respect to the solvent power and selectivi It is our invention to have discovered that fluorine exerts exactly the opposite client of either chlorine or bromine. For example, aniline and 2,4 difluoroaniline are more selective and less powerful solvents than either cbloroaniline.or aniline.

This particular action of fluorine makes it possible to change the selectivity and solvent power of selective solvents at will. The substitution 01' one or more hydrogen atoms in a selective solvent by fluorine increases the selectivity of the solvent. At the same time, non-selective solvents may be made selective by the introduction of fluorine. For example, propane is known to dissolve mineral oil entirely at temperatures of from about +50 to +150 R, except for asphaltenes. It exerts no distinctive solvent action on low viscosity index and on high viscosity index compounds, dissolving both with equal facility. It. however, two or more hydrogen atoms of We are substituted by fluorine the resultant compounds, 1,2 difluoropropane, 1,3 difluoropropane and 12.3 trifluoropropane-have teristics of selective solvents; they preferably dissolve the aromatic, hydroaromatic and unsaturated hydrocarbons leaving imdisolved the paraflinic type or high viscosity index compounds.

Anisol (Ml and ortbofluoro anisol (cm-O-Cdld'l are examples in thearomaticseriesothydrocarbonsanlsolbelng a non-selective solvent and orthofluoro anlsol selective- Ortboilunro anisol is particularly adapted forthereflningofmineraloilsandfortbeproduction of high quality lubricating oils as will be shown later on by way of examples.

Hie mnnber of fluorine atoms which must be introduced into anon-selective solvent in order allthechamh tomakeitselectivewefindwilldependtoalargc extent on the character and size of the molecule of the organic solvent. Methane and ethane may in some respects be considered selective and therefore the substitution of one hydrogen by fluorine produces the highly selective fluoride (CH1?) and ethylfluorlde (OaHsF) I whereas it is found that the corresponding chlorine derivatives 011101 and CaHsCl are non selective. In cases of a large organic radical, for instance, propyl (01111), the intioductlon of one fluorine atom is notsufllcient to produce selectivity. Propyliiuorlde (03811") is still non-selective. Only the introduction of moretban one fluorine atom the desired selectivity which we iind in diand tri-iiuoropmpane. Likewise, we

solvents methyl- 4| drocarbon groups.

- 1.1.1, triflnoroethane (meflnd the same to be true in the case of more complex aliphatic compounds. N-butylfluoride. namylfluoride, n-hexyliiuoride and n-heptylfluoride are all non-selective. and much more than one fluorine atom would have to be introduced to establish selectivity.

In the case, of non-selective aliphatic compounds which already contain other halogen than fluorine, correspondingly more fluorine must be added because oi the antagonistic eflect of chlorine and/or bromine. For example. di-bromo-monor fluoroethane, CaHaBraF. was found to be nonselective, whereas mono-bromo-difluoro-ethane. CaHJBrFs, showed excellent characteristics as a selective solvent. (See Example 1' below.) As a general rule, aliphatic halogenated solvents must contain at least as many. and preferably more fluorine atoms than chlorine and bromine atoms together in order to be selective for extracting low from high viscosity index hydrocarbons. or for separating paraflinic and non-paramnic hy- In order to substantiate iurther the above statement the following fluorine and fluorine plus otherrhaiogen containing aliphatic hydrocarbon derivatives, d as Class A, were synthesized and tested and were found to be selective with both' low and high boiling mineral oil' fractions.

sun's 4.4mm: some he llorine plus other halogen containing aliphatic solvents 'I'rifluoro-di-chloroethane... Tetr di chloro- 1,8, -mono-m-omo-monollili Ii T ,I I I f'm mnerated "I W aliphatic W are sometimes also deilned as constituents of high viscosity index and low viscosity index. respectively.

The eilcacy ot Z-monobromo-l-difluoroethane as a selective solvent and as one member of the above cited Class A will now be shown by way oi speciflc example.

' Exsuru: l

-A mixed base. dewaxed Mid-Continent motor oil was extracted with 100% plus 2x75% by volume of monobromo-di-fluoroethane at 77 F. by the multiple batch method. After each agitating the ramnate and extract phases were allowed to stratiiy and were thereupon separated. The solvent was removed from both phases by distillation under diminished pressure and the refined oil, after clay treatment at 450 F. with 10% by weight of activated clay, showed the following specifications in comparison with the untreated distillate:

Untreated I dmmm Yield t volume 100 04.1 m m 1E7 811 depend on thesiae of the aliphatic radical. Monofluoropropane is not selective in distinction to dims triiiuoropropane. This characteristic is eveninoreevidentincaseotaromatichydrocarboas because of the high solvency elect oi the benaoi ring. l'for example monofluorobensoh cm, metadifluorobennoi, m-csmra'. and 1.2.4.

Com. are no ide l. neither is the highly fluorinated meta-fluoro-trifluorotoluol, m-Cs8d" (CE). in which fluorine substiitution' was made ln'the benzol ring'as well as-in thesldeehain..' g a liowevenin certain phenylethers. for example.

anisol. (REED-CH3. and 'phenetol OsHs-O-Osfl's.

' wmch per so are not selective; selectivity could 'be by fluorination in meta position to and ethoaygrouprespectively. The

eorresponding paraderivatives. however. are not selective. a

The following table lists the t ve aromatic fluorine solvents own, a

o-iiuoroanisol.

2,4,nltro-difl summons: sadism-mum-.. pin-amiss following .areillustrativeotthe' encdlent'reflning direct Of this claasoi fluori- .derivati'veswhen usedasaeleetivesolvents. r

Insist-s2- extraeted-vrith 100 h =vol.%., I

paodnrocnnr, at -s' r. In each-of mm umm all an m: werejprop rly aid-iii aromas: 3

I Exams?) 4 10 A Pennsylvania bright stock of 25.9" A. P. I.

gravity was extracted with 100+ so vol.% orthofluoroanisol at 100" l". by the multiple batch method. After recovery of the solvent from ratflnate and extract layer by distillation at reduced is pressure a ralllnate with a viscosity index of 115 was obtained (see the following table).

Mid-Continent Pennsylvania m "to am U ted ties ntrea dhtilpate bright stock Ramm'm late Yield percent by volume it'll 58 III '72. 2 8. 5 9 2B. 2 695 6st I30 1'. 735atl30R 74. 4 8 l4]. 2 99 I02 "5 0. 32 2. 5 l. 3 5+ From the above examples it will be evidentthat out iluorinated aliphatic and aromatic selective solvents are especially suited for producing high quality motor oils and bright stocks.

35 It is further to be understood that, instead of the batch treating method described above, also the well known countercurrent operating method may be used, employing therefor either a tower; packed with Raschlg rings or provided with 40 plates, or a mixing and settling tank equipment consisting oi three or more stages.

Our invention is not limited to the use of the selective solvents of Class A and B alone. In some instances it will be of advantage to carry 45 out the extraction in the presence of an auxiliary solvent for the purpose J'of facilitating the extraction and iurther controlling the extent thereof. Such auxiliary solvents may be selected i'rom'the class of aromatic hydrocarbons, ii the to solvent power of the selective solvent is to be increased, or fromthe class of alcoholsincludi s mlyhydrlc alcohols-4! the selectivity of the selective solvent is to be improved. Also light petroleum fractions, such as propane and butane 55 may be used. Sometimes the presence of dichloro-diiluoromethane or any of the non-selective fluorine solvents, listed below under Classes C and D, during the extraction with a solvent oi Class A or B will be of advantage, dependin upon the kind 0! stock to be refined-whether it is a residual oil or a distillate-and upon the quality of the finished product which is desired.

Likewise the amount of selective solvent to be used in our extraction process will depend upon li5vlscosityandorlginottheoillobetreatedand upon the desired quality of finished product. We may use from one-half to ten volumes of solvent per volume of untreated oil. The selection of a solvent of Classes A and 13, especially suitable for 70 any partlcular oil stock, and the decision whether an auxiliary solvent of the types mentioned above should be employed together with one of our selective solvents, will be possible to those skilled in the art without diillculty, and without deviat- 75 ing from oln' invention.

our invention is furthermore not limited to the extraction of lubricating fractions or lubricating oil residues, but may also be adapted to the refining oi naphthas, kerosenes, gas oils. diesel oils and similar products. For the extraction 0! these 5 lower boiling mineral oil fractions the-hishly lective solvents of Classes A and B. as disclosed above, may be used to especial advantage. Some of these highly selective solvents, which are correspondingly low in solvent power. are for ex- 10 ample the fluorine derivatives of methane and ethane, which do not contain other halogen; or

the monoand di-fluoroaniiines.

During our study we also prepared a large number of fluorine and fluorine plus other halogen containing aliphatic and aromatic solvents, which are given below as Classes C and I) respectively, and which are not selective as between low and high viscosity index hydrocarbons, because of the predominant influence, exerted by go the organic radical and/or the chlorine and bromine present, in accordance with our theory.

Solvents of Class C Di-chloro-mono-fluorornethane CHClzF Trl-chloro-lnono-fluoromethane CClaF Di-iodo-mono-fluoromethane CHIzF Mono cloro mono bromo-monofluoromethane CHClBrF Di-bromo-mono-iluoromethane CHBrzF o Tri-bromo-monmfluoromethane CBraF Tetra-chloro-di-fluoroethane C2Cl1F2 Tri-bromo-mono-fluoroethane CaHzBrzF Trl-chioro-mono-fluoroethane CzHzClzF Tetrachloro-rnono-fluoroethane C2HCI4F Tri-chloro-difluoroethane CzHChFa Dl-brorno-mono-fluoroethane CsHaBrzF Di-chloro-mono-fluoroethylene CzHChF Tri-chloro-mono-fluoroethylene CaClaF Di-brorno-mono iluor0ethy]ene CzHBrzF 4o N-propylfluoride Call-1F iso-propyliluoridc Cali-1F N-butylfluoride C4151 N-amylfluoride CsHuF N-hexyfluoride CsHuF 5 N-heptyliiuoride CvHrsF Solvents of Class D Mono-fluoro-benzol CH5F Meta-di-fluorobenzol m-CsHd: 1,2,4 Trlfluorobenzol 1.2.4.0aH1F: p-Fluoroanisol p-CHAOCHQF p-Fluorophenetol p-CsH4(OC:HsJF p-Fluoro-bromo-benaol p-CeHiBrF o-Fluoro-chloro-benzol o-CaHrClF m-Fluoro-chlorobenzollIl-CsHsClF o-Fluorotoluol 0-CsH(CH3)F m-Fluorotoluol m-CsHuCIhJF p-Fluorotoluol p-CsHriCHzlF Trlfluorotoluol CsHs(CF1) m-Fiuoro-trlfluorotoluolm-CsHs (CF!) 1' p-Fluoro-lodo-benzo] p-CsHJF Mono-fluoro-cyclohexane--- CsHuF Mono-fluoro-naphthalene- CmHvF -These solvents are particularly adapted for as dewaxing hydrocarbon oils, because they exert little solvent power on the solid paramne hydrocarbons and substantially complete solvent action on the liquid hydrocarbons at low temperature. Our dewaxing solvents of Classes C and D may be employed in amounts of from i to 10 volumes per each volume of waxy oil to be dewaxed; in general, however, we employ from 2 00 to 400 vol.% based on waxy oil. ldoreover certain amounts of selective solvents, either of Classes A and B or any other lmown selective solvent, may be used together with the dewaxlng solvents of Classes and D. the purpose of the former being to further reduce the solubility of the wax in the solvent mixture at low temperature. The amount oi. selective solvent to be added is of course limited in that phase separation must not occur at the dewaxing temperature. In general we employ from 15 to 35 vol. solvent of Class A or B and from 85 to 65 vol. 01' Class C or D for dewaxing treatment. The dewaxing treatment may either precede or follow the extraction treatment by suitably adjusting the proportions of the selective and non-selective solvents and the temperature or extraction and dewaxing to avoid phase separation during-the dewaxing treatment and to avoid precipitation of wax during the extraction treatment.

In the claims the term selective solvent is applied to such liquids and liquefied gases as have a preferential solvent action for certain constituents of mineral oils only, such as the non-parafiinic group, including aromatic, hydroaromstic and unsaturated constituents, for example, as contrasted with the paraflinic group of constituents which are insoluble in these selective solvents; the latter group having a higher viscosity index and a higher A. P. I. gravity than the former, and being substantially free from oxidizable and gummy substances which are so undesirable in lubricating oils.

By predominantly fluorine containing as applied to a solvent. we 'mean that the substancecontains chemically bound fluorine in such amount that theeifcct oi fluorine overcomes that of the other halogens and/or organic radicals which are present in said substance and which tend to increase its solvent power, thereby G ving .the substance the properties of a selective solvent as above defined. The 'term "liquefied" means that the substance referred to is used in the liquid state, whether normally liquid or not and hydrocarbon compound and hydrocarbon derivative containing no oxygen" means -a substance in which hydrogen and carbon are directly linked with no ongen in the principal Reference is made to our companion application, Ser. No. 170,973, filed contemporaneously herewith, wherein the method of refining mineral oils with a selective solvent of the class consisting of predominantly fluorine containing aromatic hydrocarbon derivatives is specifically We claim the following as our invention:

1. A method of refining a mineral oil comprisin! extracting the oil with a selective solvent 01 the class consisting oi liquefied predominantly fluorine containing aliphatic hydrocarbon derivatives containing no oxygen, at such temperature as to produce a separation into two liquid phases, respectively containing relatively 'parafflnic and non-paraiiinic constituents. separating the phases from each other and recovering the solvent thereirom.

2- A method of refining a mineral oilcomprising extracting the oil with a selective solvent of the class consisting oi liquefied predomlnanently fluorine containing aliphatic hydrocarbon derivaflves containing no oxygen, in admixture with an auxiliary solvent, at such temperature as to produce a separation into two liquid phases, re-

spectively relatively paraflinic and nm-parailinic constituents. p rating the phases from each other and recovering the solvents therefrom.

3. A method of refining a mineral oil comprising mixing the oil with a selective solvent of the class consisting of liquefied predominantly fluorine containing aliphatic hydrocarbon derivatives containing no oxygen and adjusting the temperature to produce a separation into two liquid phases, respectively containing relatively paraflinic and non-paraihnic constituents, separating the phases from each other and recovering the solvent therefrom.

4. A method 01' refining mineral 011 according to claim 1 in which the selective solvent is monobromo-dlfiuoro-ethane.

5. A method of refining a mineral oil comprising mixing the oil with a. fluorinated aliphatic hydrocarbon of the methane series containing a suillcient amount of fluorine to make it selective as between the parafilnic and non-paraflinic constituents of the oil and adjusting the temperature to produce a separation into two liquid oil phases respectively comprising relatively paraifinic and non-paraflinlc constituents, and separating the phases from each other.

6. A method of refining a mineral oil comprising mixing the oil with a fiuorinated aliphatic hydrocarbon of the methylene series containing a suflicient amount of fluorine to make it selective'as between the parafilnic and non-paraflinic constituents of the oil and adjusting the temperature to produce a separation into two liquid oil phases respectively comprising relatively parafflnic and non-parafllnic constituents, and separating the phases from each other.

such proportions as not to produce a separation into two liquid layers at the dewaxing temperature, cooling the mixture tobelow the desired pour point and removing the precipitated wax therefrom.

8. A method of producing lubricating ofls of high viscosity index and low pour point comprising extracting the oil with a selective solvent of the class consisting of liquefied predominantly fluorine containing aliphatic hydrocarbon derivatives containing no omen at a temperature to produce two liquid phases, separating the phases and adding to the rafllnate phase so obtained before recovery of the selective solvent therefrom, Iurther amounts or the selective solvent and an auxiliary solvent of the class of benzol and its homologues, said solvents being added in such proportions as not to produce a separation into two liquid layers at the dewaxing temperature, cooling the mixture to below the desired pour point and removing the wax therefrom.

9. A method of producing lubricating oils of high viscosity index and low pour point comprisingextracting the oil with a selective solvent of the class consisting of liquefied predominantly fiuorinecontaining aliphatic hydrocarbon derivatives containing no oxygen-in the presence of an auxiliary solvent or the class oi bensol and its homologues and at a temperature to produce two liquid phases, separating the phases and adding to the railinate phase so obtained before recovery o! the solvents therefrom, further amounts of the selective solvent and auxiliary solvent. said solvents being added in such proportions as not to produce a separation into two liquid layers at the dewaxing temperature, cooling the mixture to below the desired pour point and removing the wax therefrom.

10. A method of producing lubricating oils of high viscosity index and low pour point comprising dewaxing the oil by dissolving it in a mixture of a liquefied predominantly fluorine containing aliphatic hydrocarbon derivative containing no oxygen, and an auxiliary solvent oi the class of benml and its homologues, said fluorinated solvent and auxiliary solvent being present in such proportions as not to produce a separation into two liquid layers at the dewaxing temperature, cooling the mixture to below the desired pour point. removing the precipitated wax therefrom, adding to the dewaxed oil solution so obtained. before recovery or the solvents thereirom, a further amount of the iiuorinated solvent to produce a separation into two liquid phases respectively containing relatively paraiiinic and nonparaflnic constituents, and separating the phases from each other.

11. A method of dewaxing a mineral oil by extraction with a solvent. comprising dissolving the oil in from one to ten volumes of a solvent characterized by a fluorine containing aliphatic hydrocarbon derivative containing at least three carbon atoms and not over one fluorine atom.

which solvent will not cause a separation into two liquid layers at the dewaxing temperature, cooling the mixture to about the desired pour point, removing the precipitated wax therefrom. and recovering the solvent from the dewaxed oil solution and from the wax.

12. The method of dewaxing mineral oils described in claim 11 wherein the solvent consists exclusively of non-selective fluorinated aliphatic hydrocarbon derivatives.

13. A method of dewaxing a mineral oil by extraction with a solvent, comprising dissolving the oil in from one to ten volumes of a solvent characterized by a fluorine containing aliphatic hydrocarbon derivative free from oxygen and containing at least three carbon atoms and not over one fluorine atom, which solvent will not cause a separation into two liquid lasers at the dewaxing temperature, cooling the mixture to about the desired pour point, removing the precipitated wax therefrom, and recovering the solvent from the dewaxed oil solution and from the wax.

ERNST TERR-ES. JOSEF MOOB. BANS RAMBER.

CERTIFICATE OF CORRECTION.

Patent lie. 2,162,682.

June 13, 1959'.

' smrsr rnnnss, ET AL.

lit is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows} Page 5,!115'1: column, lines 26 and 27, Example 5, inthe first coluninof the table, for

Viscount read Viscosity} line 52,!orthe word "cut" end calm, as a s the table, for lionethai: the said Letters Patent should be read that the same may conform to the record of si ned and sealed this z thna or August, A. n. 19 9'.-

.(SeaJJ Ie'slie; Fraser,-

. read our; seccloro! read lionovchloroq with this correction met-ens the case lathe Paten i Office.

acting oon'niisslcner oi. Patents;

homologues and at a temperature to produce two liquid phases, separating the phases and adding to the railinate phase so obtained before recovery o! the solvents therefrom, further amounts of the selective solvent and auxiliary solvent. said solvents being added in such proportions as not to produce a separation into two liquid layers at the dewaxing temperature, cooling the mixture to below the desired pour point and removing the wax therefrom.

10. A method of producing lubricating oils of high viscosity index and low pour point comprising dewaxing the oil by dissolving it in a mixture of a liquefied predominantly fluorine containing aliphatic hydrocarbon derivative containing no oxygen, and an auxiliary solvent oi the class of benml and its homologues, said fluorinated solvent and auxiliary solvent being present in such proportions as not to produce a separation into two liquid layers at the dewaxing temperature, cooling the mixture to below the desired pour point. removing the precipitated wax therefrom, adding to the dewaxed oil solution so obtained. before recovery or the solvents thereirom, a further amount of the iiuorinated solvent to produce a separation into two liquid phases respectively containing relatively paraiiinic and nonparaflnic constituents, and separating the phases from each other.

11. A method of dewaxing a mineral oil by extraction with a solvent. comprising dissolving the oil in from one to ten volumes of a solvent characterized by a fluorine containing aliphatic hydrocarbon derivative containing at least three carbon atoms and not over one fluorine atom.

which solvent will not cause a separation into two liquid layers at the dewaxing temperature, cooling the mixture to about the desired pour point, removing the precipitated wax therefrom. and recovering the solvent from the dewaxed oil solution and from the wax.

12. The method of dewaxing mineral oils described in claim 11 wherein the solvent consists exclusively of non-selective fluorinated aliphatic hydrocarbon derivatives.

13. A method of dewaxing a mineral oil by extraction with a solvent, comprising dissolving the oil in from one to ten volumes of a solvent characterized by a fluorine containing aliphatic hydrocarbon derivative free from oxygen and containing at least three carbon atoms and not over one fluorine atom, which solvent will not cause a separation into two liquid lasers at the dewaxing temperature, cooling the mixture to about the desired pour point, removing the precipitated wax therefrom, and recovering the solvent from the dewaxed oil solution and from the wax.

ERNST TERR-ES. JOSEF MOOB. BANS RAMBER.

CERTIFICATE OF CORRECTION.

Patent lie. 2,162,682.

June 13, 1959'.

' smrsr rnnnss, ET AL.

lit is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows} Page 5,!115'1: column, lines 26 and 27, Example 5, inthe first coluninof the table, for

Viscount read Viscosity} line 52,!orthe word "cut" end calm, as a s the table, for lionethai: the said Letters Patent should be read that the same may conform to the record of si ned and sealed this z thna or August, A. n. 19 9'.-

.(SeaJJ Ie'slie; Fraser,-

. read our; seccloro! read lionovchloroq with this correction met-ens the case lathe Paten i Office.

acting oon'niisslcner oi. Patents; 

